brcmfmac: fix error return code in brcmf_cfg80211_connect()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 3b1e0a7b ("brcmfmac: add support for SAE authentication offload")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Reviewed-by: Chi-hsien Lin <chi-hsien.lin@infineon.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1605248896-16812-1-git-send-email-zhangchangzhong@huawei.com